Warnings for the entire home. Connect all carbon monoxide detectors (CO detectors) throughout your home for comprehensive protection. When an alarm is triggered by carbon monoxide, all CO detectors will sound. Advanced Figaro sensor. The X-Sense carbon monoxide detector detects and responds immediately to CO levels in the air. Replaceable batteries and low battery warning. Three replaceable AA batteries provide constant protection against CO, even during power outages. You will be notified when it’s time to replace the batteries. Large informative LCD display. Displays CO levels in real-time starting from 30 ppm. It also shows the operational status and battery life, so you can have peace of mind. Expandable wireless network. Up to 24 wireless X-Sense Link+ detectors can be connected using high-frequency technology.